FE Power Forums
FE Power Forums => FE Technical Forum => Topic started by: 64PI on July 25, 2019, 11:20:00 AM
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Whats the smallest someone has safely gone? I'm running edelbrock heads with precision pumps bronze bushed rockers. Precision pump M-57HV oil pump. I have a holley 78 jet in the heads now. Priming the pump to 75psi with the valve covers off will flood the heads. I have .003" main clearance and .0025" on the bbc rods. Engine hot @ idle is about 5psi, 50psi @ cruise and 70-75psi @ WOT. The block is half filled and the car runs warmer than I would like. I'm installing an aluminum radiator, electric fan and water pump. Also installing a oil cooler.. I'm just curious if I can go a little smaller to keep some oil down low without completely starving the rockers.
Fred
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The rockers need very little oil. Your problem with overly restricting oil to the heads is failure to cool the valve springs. They are cooled only by oil.
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I run a .070" orifice for bushed rockers.
With that being said, it's not a big problem if you get a lot of oil up there. That's what the drains are for.
Block filling isn't an issue. It's not the coolant temperature that will rise, it's the oil temperature.
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BTW, the cruise and WOT oil pressures are perfectly fine and normal. It's the idle pressure that's whopper-jawed.
What viscosity oil are you running?
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For reference, I've got pretty much the same hardware setup with maybe a little less bearing clearance and run 20 at idle even when engine is up at 200 degrees. 5 does seem awful low and not related to the head restriction. 10w30
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I am going to offer a contrary opinion on your idle oil pressure. I don't expect very many to agree with me and I'm okay with that. I am comfortable with my opinion on this one.
Your idle oil pressure is fine. In that regard, it doesn't matter what weight oil you're using or what your idle speed is. Idle speed can often make a significant difference in idle oil pressure. You mid and upper rpm oil pressure is also fine.
The reason I think your idle pressure is okay? Well, you generally don't see a specification for idle oil pressure. Not by manufacturers or anyone else. Oil pressure references are usually specified as oil pressure @ 2,000 rpm or there abouts. One of the reasons you don't usually see a spec for idle oil pressure is that the engine is under very low load. It's making just enough power to keep itself turning over. Because of the very low cylinder pressure, there's very little load on the bearings. As long as the engine is moving oil over the bearings, you're fine.
The other reason is all engines are subject to stacking tolerances. These things are not being built to aerospace specifications so bearing clearances may not be completely uniform throughout the engine...particularly in the camshaft where most oil pressure is lost. It's good enough to get the job done.
Some old timers may recall this, but it was pretty common for the oil light to flicker when you were sitting at a stop light at idle. The pressure sensor would turn on the light around 5psi. This was with brand new cars. Ford's solution to customer concerns about low oil pressure? They raised the idle by 50 rpm and that turned out the light.
If you were concerned about idle oil pressure you could try running a slightly higher idle or, depending upon what you're now using, running a heavier oil. But I don't think you need to.
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I am going to offer a contrary opinion on your idle oil pressure. I don't expect very many to agree with me and I'm okay with that. I am comfortable with my opinion on this one.
Your idle oil pressure is fine. In that regard, it doesn't matter what weight oil you're using or what your idle speed is. Idle speed can often make a significant difference in idle oil pressure. You mid and upper rpm oil pressure is also fine.
The reason I think your idle pressure is okay? Well, you generally don't see a specification for idle oil pressure. Not by manufacturers or anyone else. Oil pressure references are usually specified as oil pressure @ 2,000 rpm or there abouts. One of the reasons you don't usually see a spec for idle oil pressure is that the engine is under very low load. It's making just enough power to keep itself turning over. Because of the very low cylinder pressure, there's very little load on the bearings. As long as the engine is moving oil over the bearings, you're fine.
The other reason is all engines are subject to stacking tolerances. These things are not being built to aerospace specifications so bearing clearances may not be completely uniform throughout the engine...particularly in the camshaft where most oil pressure is lost. It's good enough to get the job done.
Some old timers may recall this, but it was pretty common for the oil light to flicker when you were sitting at a stop light at idle. The pressure sensor would turn on the light around 5psi. This was with brand new cars. Ford's solution to customer concerns about low oil pressure? They raised the idle by 50 rpm and that turned out the light.
If you were concerned about idle oil pressure you could try running a slightly higher idle or, depending upon what you're now using, running a heavier oil. But I don't think you need to.
I look at it this way.....
I build a ton of FE's, with the same bearing clearances and the same oil pump, and I have never witnessed anything lower than 20-25 psi on a hot idle. Even with a standard volume/standard pressure pump, I still see that much idle pressure.
Based on just a very large sample size, I can say that something "ain't right".
Now, it could be a gauge that's off, or it could be the combination of a lighter viscosity oil with a poured block and no oil cooler. Either way, 5 psi at hot idle isn't normal and I'd be checking it out.
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Okay, I'm not surprised you don't see it as normal. But is it harmful? You write what normal idle oil pressure is. What establishes a norm? What happens if it's 40psi or 50psi at idle? I've seen that plenty of times. I mean, the often stated rule is that you need 10psi/1000rpm and that gets thrown around as though it were gospel. Is that always the target pressure? If you had a customer engine with great oil pressure all the way around but with 5psi at hot idle, what would be your remedy?
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Okay, I'm not surprised you don't see it as normal. But is it harmful? You write what normal idle oil pressure is. What establishes a norm? What happens if it's 40psi or 50psi at idle? I've seen that plenty of times. I mean, the often stated rule is that you need 10psi/1000rpm and that gets thrown around as though it were gospel. Is that always the target pressure? If you had a customer engine with great oil pressure all the way around but with 5psi at hot idle, what would be your remedy?
If the gauge and oil were known to be correct, I'd probably be tearing it down to see what's wrong.
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what does the oil pressure do at idle, 2500 rpm, and 4500 rpm? Not suggesting this is the issue but it has happened to a few folks.
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Brad Penn 10W30 oil.. 3/4 groove main bearings. Idles at 900rpm in park. At 1200rpm it starts to climb... 1500 rpm 25-30 psi.
The oil pressure is very responsive to RPM and does not fluctuate at cruise or wide open or even holding steady at 1500. No debris in the oil filter.. All the galley plugs are in it. EDM lifters. No noises, clings, clangs or bangs. Engine runs very strong.. Just runs on the warmer side of life which I am addressing. I thought I could get away WITHOUT an oil cooler and I don't think that is possible with a half filled block. Plus my 2 1/8" cross over headers are not helping any.
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Brad Penn 10W30 oil.. 3/4 groove main bearings. Idles at 900rpm in park. At 1200rpm it starts to climb... 1500 rpm 25-30 psi.
The oil pressure is very responsive to RPM and does not fluctuate at cruise or wide open or even holding steady at 1500. No debris in the oil filter.. All the galley plugs are in it. EDM lifters. No noises, clings, clangs or bangs. Engine runs very strong.. Just runs on the warmer side of life which I am addressing. I thought I could get away WITHOUT an oil cooler and I don't think that is possible with a half filled block. Plus my 2 1/8" cross over headers are not helping any.
Most filled blocks need oil coolers, hard to get away from it. Makes oil temp go up.
I think I'd try some 20W50 BP oil to help with the higher temperatures and if that didn't work, I'd be looking to see what's up. Old worn out pickup 390's will make the oil pressure light come on. New engines should not.
It might be worth it to try another oil pressure gauge first.
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Brent- have you ever checked oil temp before on a filled block? Just curious what kind of difference I will see in temperature by adding the cooler. And the better question is what kind of affect does that temperature difference have on viscosity? I picked up a pretty decent size cooler. I believe it’s 32 row 11”x8”x2”.
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I take oil temp readings on all the engines I dyno. I see 10-15 degrees difference usually.
Got another gauge to try real quick?
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My oil cooler is a little smaller. An Earl's 16 row plate cooler. I've never measured the temps but it's a pretty big drop. At idle, the oil hose going in is too hot to touch for more than a couple seconds. Oil coming out of the cooler is a lot cooler. Cool enough you can hold the hose.
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I have another gauge to try I can pull from my truck that I believe is accurate. Is it possible that the gauge could be accurate on the higher end of the PSI and off on the low?? Now you’ve got me wondering about the copper supply line too.
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It's possible that it's off on the entire scale......like maybe it's showing 20 at idle and really 85 at wide open song.
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Ah, some fun Thursday afternoon banter, but no beer.
Just the fact that it is low in and of itself is not proof of a problem but certainly and indicator of something different as Brent states.
If it were for sure 5psi everywhere within the engine then maybe 5 is ok at idle, the lower it is at idle though the less room you have for variability throughout the engine. Oil has some tortuous pathes to navigate, the highly tortuous pathes may see very little if any oil at that pressure where you want it, just like water, takes the path of least resistance. Also, low pressure means that even if the oil is getting to location there may be no oil ingress for tight bearing locations as the pressure can not overcome other forces.
I also do not buy into the low load argument. At low loads things are bouncing around within the given clearances, sure they may not have the load of higher rpm but I for one for sure would not want to thin or no lube on a bearing rotating just fast enough to clank back and forth across the clearance gap, different kind of wear probably but not good.
The oil is the bearing and the bearing is the oil distributor/retainer across any given surface.
I also look at these things this way, what are the limits and how bad is it if you get there?
Well we all know 0psi is the lower limit and it is very very bad, so 1 or 2 psi is likely very bad, 3 or 4 psi is likely bad, you get the idea.
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Okay, I'm not surprised you don't see it as normal. But is it harmful? You write what normal idle oil pressure is. What establishes a norm? What happens if it's 40psi or 50psi at idle? I've seen that plenty of times. I mean, the often stated rule is that you need 10psi/1000rpm and that gets thrown around as though it were gospel. Is that always the target pressure? If you had a customer engine with great oil pressure all the way around but with 5psi at hot idle, what would be your remedy?
If the gauge and oil were known to be correct, I'd probably be tearing it down to see what's wrong.
Me too, something isn’t right. If 5 psi at the gauge they back of the motor is likely lower.
Maybe cam bearing clearance, maybe oil galley plug, maybe clearances aren’t what you think, maybe pickup sucking air, maybe oil mods gone wrong. Harmful, who knows, but there is a reason and that reason won’t get better
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For what it may be worth, all the FE engines I've ever owned, (Except a '63 390-300 for a couple of months during a somewhat complex trade situation) have been performance oriented. I find that an idle of much over 1K is a little bit wearing on me as the driver. A thousand is OK and I usually try for about 850. The rise in oil pressure at that part of the rev curve is almost vertical.
What does your gauge say at 1000? 900?
At one point, I put a new set of rod bearings in a worn '64 390-330 that also had a somewhat 'lumpy' cam of unknown origin. That otherwise 80K miles-on-the-speedo engine jumped up to 25 at idle and 60+ past 3000.
Can you get to a livable level just by up-ing the idle a bit?
KS
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Rebuilt the 352 in my F100 25 years an 40,000 miles ago just to move it around till I built new mill
Still driving it .. lol ..... main and rod journals looked had been turned with a cats claw
Inserts were worn past the copper, had to rat tail file the top ridge off to use a ridge reamer
All top rings were broken into 2 or 3 parts
5 of the second rings the same
Mill had around 350,xxx miles on it, the oil filled air cleaner was usually low on oil
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New full groove mains, rods, cast rings.... original small body oil pump
Cold, 40 idle ..... 70 psi on freeway
Hot, 25 idle ..... 60 psi on freeway ( Texas weather )
Puffs a bit at start, idles nice and runs smooth
Ricky.
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I guess the thing that I don't understand is that IF there were excess clearance or a internal oil leak somewhere, wouldn't I be seeing a drop in pressure across the board? Like I said the only time it dips to 5psi is after the engine is hot and at idle in gear(900rpm). How much volume is getting to the bearings at 5psi, I don't know... Initial start up the gauge goes to 75.... after I get heat in the engine (160-180) and back out of the shop and it will idle on its own at 900 rpm the oil pressure is still reading in the 40-50 psi range. Seems normal enough there. The drop is only after I run the car and get the water up to 190-200 (who knows where my oil temps are at this point).
If a galley plug was missing, or the pump was sucking air or the clearances are 2X the size I measured.... Would it still be able to get 75psi at WOT and hold steady and not fluctuate? You would think you would see some sort of fluctuation.
I have 3 different gauges to try. I'm going to hook them all directly to the oil filter housing. Spin the pump with a drill while the engine is cold and see what each of them read. RPM will be a constant. Oil temp will be a constant. The only variable will be the gauges.
This engine used to have 10 psi hot at idle when my mains were @ .0025".. The only thing different during the rebuild is using cleveland mains to open up the clearance to .003"... The engine DID take out the cam bearings but I do not believe that was a oil related issue due to the fact that there were no signs of oil starvation to the cam bearings, the main bearings looked as good as the day I put them in and the rod bearings also looked beautiful. You would think if I had a oil delivery issue the rod bearings would be the first to go.. Especially when I was spinning the engine to 7500 rpm..
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A internal oil leak can be large enough at low rpm to show a big drop on the guage, but your HV pump can overcome it and show steady pressure at higher rpm. 5 psi is problematic. I've had FE's for 50 + years, had some at 13 at idle, never 5.
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I switched to Brad penn oil and my idle oil psi dropped about 8-10 psi. I would try a different oil.
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I guess the thing that I don't understand is that IF there were excess clearance or a internal oil leak somewhere, wouldn't I be seeing a drop in pressure across the board? Like I said the only time it dips to 5psi is after the engine is hot and at idle in gear(900rpm). How much volume is getting to the bearings at 5psi, I don't know... Initial start up the gauge goes to 75.... after I get heat in the engine (160-180) and back out of the shop and it will idle on its own at 900 rpm the oil pressure is still reading in the 40-50 psi range. Seems normal enough there. The drop is only after I run the car and get the water up to 190-200 (who knows where my oil temps are at this point).
If a galley plug was missing, or the pump was sucking air or the clearances are 2X the size I measured.... Would it still be able to get 75psi at WOT and hold steady and not fluctuate? You would think you would see some sort of fluctuation.
I have 3 different gauges to try. I'm going to hook them all directly to the oil filter housing. Spin the pump with a drill while the engine is cold and see what each of them read. RPM will be a constant. Oil temp will be a constant. The only variable will be the gauges.
This engine used to have 10 psi hot at idle when my mains were @ .0025".. The only thing different during the rebuild is using cleveland mains to open up the clearance to .003"... The engine DID take out the cam bearings but I do not believe that was a oil related issue due to the fact that there were no signs of oil starvation to the cam bearings, the main bearings looked as good as the day I put them in and the rod bearings also looked beautiful. You would think if I had a oil delivery issue the rod bearings would be the first to go.. Especially when I was spinning the engine to 7500 rpm..
Pressure is indeed the measurement of resistance, so you are correct that if it had a big dump, you should not have cold pressure, or any pressure later
However, think about how an FE measures oil pressure, it is essentially (except for a short run) right after the pump and just before all the galleys that go everywhere
Based on that, there is always going to be some resistance to flow from the galleys and intersections themselves, to include the filter mount itself as it exits a round about pattern.
5 psi is low hot, real low, silly low...so I do understand that you are trying to work through this logically, but it takes something real loose, wrong oil, real loose oil pump....when it's cold, that resistance enroute to the moving parts is greater, when the oil thins it's less, but it isn't right
I'd be sure a second gauge says the same thing, I'd likely swap out the oil and filter to something different, but if it didn't change, I'd be looking inside.
I do like your plan, it also allows you to listen through the distributor hole, a plug leaking will usually gurgle
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Short answer is yes - you can go lower on restriction - we go to .060 pretty often with no real visible or documented ill results. You'd be amazed to see how much oil can flow through a .060 diameter hole.
Given that the pressure gets normal pretty quickly you are probably OK, but that 5 reading is awfully low.
You are already planning to go through the normal stuff - oil, filter, gauge.
On an older block it could be lifter to lifter bore clearances - hard one to fix in the car (like impossible...)
On really problematic ones we have pre-oiled with the pan off to "see" the big leaks. Use a big Home Depot masonry tray, a cut off oil pump pickup, and a few feet of 5/8 heater hose to make a remote pan. Spin the pump with a drill and watch the waterfall.
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How about using compressed air with a regulator to try and identify the source of a leak? Or would you just hear air pissing out from every bearing surface? Would you be able to hear air passing through a "loose" oil pump?
IF I do not see any improvements with putting the oil cooler on and keeping the engine at a manageable temperature with my new cooling set up, I'm going to start looking deeper. I'm very confident in my bearing clearances and measurements. So I would like to think I can take that out of the equation. All the galley plugs were put in with sealer.. The cam retaining bolts with loc tite. The only thing I could think to question are the oil pump, It is used but I cleaned it and everything looked fine. I also question the canton pickup tube.. all the welds looked fine and I did not see any cracks.. But so did their oil pan I put on 4 years ago that started leaking after I put heat in the engine.. So maybe there is something leaking there.
I appreciate everyone's input and help on this and I hope to resolve the issue hopefully without destroying anything or having to completely tear down the engine.
Fred
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Let me give you an example of a recent SBC I had a chance to play with
Without the proper collar to block off an oil passage where the distributor goes, oil pressure shot up as the huge passage dumped oil. As it did so, it made a hell of a lot of noise like a gurgling sewer pipe, it was very clear.
Depending on which galley, it could be blatantly obvious when you spin the primer tool. Behind the distributor or the angled ones you see through the distributor hole will be obvious. The rear ones under the intake, not as much, and we know the rear of the block isn't leaking because it would pee on the floor LOL
You may find the culprit immediately in the distributor hole or near it
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I had an oil galley come out behind the distributor. It was at the 22 psi range at idle with hydraulic lifters but dropped to 3 with dumbbell lifters. You have all the same pressure ranges I had with that engine and an HV oil pump.
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I put the restrictions in my heads, .075 restriction. The restriction is drilled at the rear upper galley that feeds #5 main, the feed hole from the pump to the adapter is drilled to 7/16" and the pump mounting area on the block is drilled to 5/8 and blended. I have screw in plugs in all locations. I am running Precision Oil Pump's blueprinted HV pump.
I have the mechanical gauge in my '67 Shelby. 80 LB cold. ( Penn 30WT) hot idle is 35-40 and cruise is about 70LB at 3200 RPM.
Plenty of oil up top as well.
-Keith
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I had a CJ engine with low idle oil pressure and I agree with Barry. I would suspect the lifter bores being loose or out of round. I learned it was a big deal to fix. You either need a fixture to properly bore the holes oversize for a bushing or for a larger (Mopar) lifter or someone with a CNC setup that has the right program.
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Would someone add more info on the Mopar lifters?
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I don’t like the idea of just boring to a .903” size unless you bore large enough for bushings to use them.
You need a BHJ lifter tru fixture to accurately install lifter bore bushings.
A Morel lifter is slightly oversized to help with loose bores.
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Holy crap, we got into the weeds on speculation and diagnosis.
Was a second gauge ever used to verify readings? The most likely scenario is your gauge is off and your oil pressure is just fine.
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I also think 5 psi is low i fixed a 360 that was rebuilt and they left the plug out below the dist and it had 15 with a hv oil pump.I am not like everyone else on restrictors they are ok on a drag race motor but on a stock rebuild or on a car with gears that spins them hard for a long time the valve springs get hot and need the oil.At one time a posting by Bud Moore i think thats who it was made a valve spring tester and they got hot so fast it was a eye opener.I had a small block with oil pressure like yours and the relief valve in the pump was stuck open.
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First of all, restrictions don't keep oil down to a trickle. There is PLENTY of oil up top. Even with the .090 there is probably a half quart up top. We're not talking about dry. It serves its purpose especially with standard capacity pans.
-Keith
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Fred, This is a long shot, but does your Oil Filter Bracket pad look like this (1st pic). See the the little hole and it looks like the shadow of the old gasket is right to the edge of the hole, possible leak point. You can plug it with Pipe plug as in Pic 2. Don't ask what the hole is or was used for, no one seems to have a clear answer but it can be found on older blocks, it just goes thru the skirt and dumps back into the pan.
As for your concern with the cross under header tubes, take a piece of the sticky back heat reflective sheet and stick it to the bottom of your pan. Also does 5&6 header tubes drop down close to your filter? If so, take some of the same reflective material and stick it on the back side of your filter. How much does this help I don't know but at least I tried.
Bill
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*UPDATE*.... Got the car back running. I put in an aluminum radiator, Spal electric fan, Meizer water pump and a oil cooler. Car runs between 185-190. Even after a hard run and a long idle it stays right at 190. The oil pressure in gear at idle (900-1000) is 15PSI with 10w30 brad penn. The car is running great now that I can maintain a decent temperature. I'm considering switching to 20w50 due to the larger main clearances. I also bought a bore scope that syncs to a iphone. I'm thinking about priming the engine looking to see if I can see any excess oil coming from the lifters or any leaking plugs. The mention of lifter bores being worn might make some sense. The block is from a late 60's dump truck and was .030" over when I got it and cleaned up at .060" over. So I'm sure it had a busy life. I also ran solid roller lifters in it for a very short period of time, the oil passages to the lifters were completely blocked off and I remember the oil pressure being higher at idle. I'm running EDM solid lifters with full oil to them now. I'm really liking the electric fan and water pump set up. I can shut the car off and knock 40 degrees out of the engine within minutes.
Fred
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I have a 65 jet in my CJ heads .
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I tried restricting rocker oiling to .043"...Burnt up the #1 exhaust rocker adjuster and push rod. I now use .062" drilled/threaded plugs.